PlGF-2 and PlGF-3

Placenta growth factor (PlGF) is a dimeric growth factor in the PDGF/VEGF family. Alternative splicing generates at least three human PlGF isoforms PlGF 1, PlGF 2, and PlGF 3. PlGF 2 is the only isoform that contains a heparin binding region. It is expressed by villous trophoblasts, decidual cells, erythroblasts, keratinocytes, and some endothelial cells. PlGF competes with VEGF for binding and activating VEGF R1/Flt 1. This results in increased angiogenesis by making more VEGF available for activation of VEGF R2. PlGF 2 also exhibits heparin dependent binding of Neuropilins-1 and 2 which serve as VEGF co-receptors. It can inhibit nerve growth cone collapse and induce monocyte production of inflammatory cytokines including VEGF.